Stepless variable change-speed gear with roller bodies



May 10, 1949. Y J KQPP 2,469,653

STEPLESS VARIABLE CHANGE-SPEED GEAR WITH ROLLER BODIES Filed Jan. 14,1946 2 Sheets-Sheet l M/VEN TOR 2,469,653 FEED May 10, 1949. J, KOPPSTEPLESS VARIABLE CHANGE-S GEAR WITH ROLLER BODIES 2 Sheets-Sheet 2Filed Jan. 14, 1946 Patented May 10, 94 9 f.

UNITED s'rA'r 1:s \PATENT OFFICE s'rnruiss VARIABLE CHANGE-SPEED GEARwrrn ROLLER BODIES Jean Kopp, Berne, Switzerland Application January14,1946, Serial No. 641,039 In Switaerland February 1, 1945 l My presentinvention relates to stepless changespeed gearing comprising a drivingand a driven Claims. 01. 74200) of a spherically shaped collar 5|; whilethe two ends of the said axles 50 are guided in radial grooves 52 of thecasing 22. The said frame 53- is mounted rotatively adjustable in thecasing 22, that is, there is a sliding fit between the casing 22 and thecover 2| thereof.

The said disc 53 may be rocked by means of a lever l6 between theterminal positions shown by the dash-and-dot lines on top of Fig. 3. Byswinging the lever IS in one direction or the other, the axles 50 of theballs 3 are tilted. In

ting surfaces, which spring acts axially against one surface ofrevolution and is so disposed that the axial thrusts exerted by the twosurfaces of revolution are taken up by one of the said shafts,

that is, no axial thrusts are'transmitted to the section of suchembodiment; and

Figs. 4 and 5 modified designs in axial sections.

In the embodiment, shown in Figs. 1-3, a pulley body 2, provided withthe one surface of revolution. is keyed to the shaft I. The latter isjournailed in a ball bearing in the casing 22 which is provided with a,cover 2| in which a counter pulley body '6 provided with the othersurface of revolution, is rotatably mounted and secured to the flange Iof a shaft 8. The extension of the shaft I is journalled in the saidflange 1 in the ball bearing l3 and inside the surface of revolution 6in a ball bearing 26 also. The shafts land 8 and the bodies ofrevolution 2 and 6 are coaxial.

Five roller bodies, formed as balls 1, are in frictional contact withthe surfaces of revolution embodied on the bodies 2 and 6. and with arotatable encircling ring 5. Each ball 3 is mounted .on an axle 50passing therethrough, which latter in the vicinity of one of its ends,is guided in a curved slot 52 of a disc-like frame 83, by means.

Fig. 1 the lever I6 is in its mean position, wherein the axles 50 of theballs 3 are parallel to the com--.

mon axis of the shafts l and 8, and the points of contact of the balls 3with the surfaces of revolution of the bodies 2 and 8, which latter areof equal diameter, are equally spaced from the axles 50 of the balls,whereby the gear ratio is unity or 1:1. When the lever I6 is moved intothe left-hand terminal position of Fig. 3, the axles 50 of the balls aretilted into the position shown in Fig. 2, wherein the points of contactof the balls with the surfaces of revolution of the bodies 6 and 2 arespaced unequally from the axes of rotation of the balls. Referring toFig. 2, if I is the driving shaft, the driven shaft 8 will run at lessspeed; and conversely, when the lever I6 is thrown into the right-handterminal position.

In order to produce the necessary contact pressure between the surfacesof'revolution and the balls 3, a helical spring H is provided, which atone end abuts against a nut 12 mounted on the extension of the shaft l,and at its other end against a ball bearing Ill on the body 6. Bydisplacing the nut l2 on the threaded stub extension of the shaft I, thetension of the spring H is adjusted. The axial components of thiscontact pressure of the bodies 2 and 8 against the balis3 are nottransferred onto the casing 2|, 22, but are taken up by the shaft I, andthe radial components by the ring 5. The latter is floating,

' 3 mately of bail shape. The latter also may so deviate from the truespherical shape that the contact pressure changes in accordance with thetransmission ratio. In the case of great speed reductions, for example,and with high initial tion contact along this grooved portion of theballs surface.

As shown in Fig. 5, the balls 3" may be provided with a groove 54, inwhich the outer ring I is engaged. In order to permit of laterallydisplacing the ring 5' when tilting the axles 50 of the balls 3", asshown in Fig. 5 by dotted lines, the spherical shape of the balls wouldhave to be corrected so as to allow the, balls upon tilting to slightlydeviate inwardly. By virtue of such correction,-there results a changein the contact pressure on the surfaces of revolution of the bodies I.and 8, which tends to change the con- ;.ta'ct pressure in'correspondencewith. the torque .transmitte'd ,b"y the surfaces of revolution. .When,for: example, the torque onthejdriving shaft is'high in the case of aspeed reduction,

. the balls are pressed with greater force against the incoming thanagainst the outgoing surface of revolution.

By selecting the number of balls in the gearing according to my presentinvention, a sumciently great number of power transmitting contactpoints between balls and surfaces of revolution may be provided so as tokeep the specific contact pressure comparatively small, and yet ensure apositive transmission. The wear thus also may be kept relatively low,affording a long life in combination with a simple construction.

What I claim and desire to secure by Letters Patent is:

1. A steplessly variable change-speed gear, comprisin in combination, adriving shaft, a driven shaft coaxiaiiy arranged to the driving shaft,two bodies respectively provided with a frictional surface shaped as asurface of revolution and fixed to said driving and driven shaftsrespectively, a plurality of ball-shaped roller bodies in frictionalengagement with said surfaces of revolution, a rotatable ring againstwhich all of said roller bodies abut, an axle for each roller bodyaround which the respective roller bodies rotate, means forsimultaneously rocking said axles for causing a stepless variation ofthe transmission ratio between said driving and driven shafts, and meansproviding contact pressure between said surfaces of revolution and saidroller bodies, said ring taking up the radial components of saidcontactpressure.

2. A steplessly variable change-speed gear, comprising in combination, agear casing provided with radial slots, a driving shaft, a driven shaftcoaxiaiiy arranged to the driving shaft,

two bodies each provided with a frictional surface formed as a surfaceof revolution and fixed to said driving and driven shafts respectively,a plurality of ball-shaped roller bodies in frictional engagement withsaid surfaces of revolution, a rotatable ring against which all of saidroller bodies abut, an axle for each roller body around which therespective roller bodies rotate, the ends of each axle being guided insaid radial 4 slots of the casing, is rotatable disc having a curvedslot for each roller body axle and cooperating with a portion or theaxle near one of the ends of the axle, whereby an angular displacementof said disc causes a simultaneous rocking of said axles for causing astepless variation of the transmission ratio between said driving anddriven shafts, and means providingconbodies abut, an axle for eachroller body around which the respective roller bodies rotate, a collarprovided on said axles near one end of same and the ends of each axlebeing-guided in said radial slots of the casing, a rotatable disc havinga curved slot for each. roller body axle and cooperating with saidcollar, whereby an angular displacement of said disc causes asimultaneous rocking of said axles for causing a stepless variation ofthe transmission ratio between said driving and driven shaft, and meansproviding con-;

tact pressure between said surfaces of revolution and said rollerbodies, said ring taking up the radial components of said contactpressure.

4. A steplessly variable change-speed gear, comprising in combination, adriving shaft, a driven shaft coaxial with said driving shaft, twobodies provided with frictional surfaces shaped as surfaces ofrevolution, one of said bodies being fixed to one of said shafts and theother being non-rotatably fixed to the other shaft and axiallydisplaceably mounted on an extension of said one shaft, a plurality ofballs in frictional engagement with said surfaces of revolution, aspring acting upon said displaceably mounted body for providing contactpressure between said balls and said surfaces, a member displaceablyfixed to said shaft extension and forming an abutment for said spring,whereby the axial component of the contact pressure is taken up by saidshaft extension, a rotatable ring against which all of said rollerbodies abut, an axle for each roller body around which the respectiveroller bodies rotate, and means for simultaneously rocking said axlesfor causing a stepless variation of the transmission ratio between saiddriving and driven shafts.

5. A steplessly variable change-speed gear, comprising in combination, adriving shaft, a driven shaft arranged coaxially with the driving shaft,two bodies each provided with a frictional surface shaped as a surfaceof revolution and fixed to said driving and driven shafts respectiveiy,a plurality of approximately ball-shaped roller bodies in frictionalengagement with said surfaces of revolution, a rotatable ring againstwhich all of said roller bodies abut, an axle for each roller bodyaround which said roller bodies rotate, means for simultaneously rockingsaid axles for causing a stepless variation of the transmission ratiobetween said driving and driven shafts, means providing the requiredcontact pressure between said surfaces of revolution and said rollerbodies, said ring taking up the radial 5 components of said contactpressure, the shape UNITED STATES RA'I'ENTS of said balls deviating fromthe true spherical Number 7 Name Date shape in such manner that onrocking the axles 2,164,489 Berliner July 4, 1939 of said balls thecontact pressure with sald fric- 2,164,490 Berliner July 4, 1939 tlonalsurfaces varies in accordance with the 5 2,252,630 Heer Aug. 12, 1941torque to be transmitted. 2 318 471 Dodge Ma 4 1943 JEAN'KOPP. y

2,389,589 Arter Nov. 27, 1945 REFERENCES CITED FOREIGN PATENTS Thefollowing references are of record in the 10 Number Country Date file ofthis patent: 527,346 Germany June 17, 1931

